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What This Guide Helps With
This guide addresses situations where the Drager Perseus anesthesia machine:
- Displays FiO₂ readings that do not match the set value.
- Delivers incorrect oxygen concentrations to the patient circuit.
- Triggers alarms related to oxygen supply, hypoxia, or gas mixture inconsistencies.
Focus is on logical, external, and easily verifiable checks before assuming internal component failure.
Step-by-Step Troubleshooting
Verify Oxygen and Air Supply
- Ensure both the oxygen and compressed air sources are connected and turned on.
- Check that pipeline pressures are within the normal operating range (usually 50–60 psi).
Why: Inadequate supply pressures can directly cause FiO₂ deviations.
Inspect Supply Hoses and Connections
- Look for kinks, leaks, or disconnections in oxygen and air hoses.
- Ensure quick-connect fittings are fully seated.
Why: Leaks or partial disconnections can dilute oxygen concentration.
Check Flowmeters and Vaporizers
- Confirm that flowmeter readings correspond to set values.
- Ensure vaporizers are properly seated and turned off if not in use.
Why: Improper flow or vaporizer placement can affect FiO₂ delivery.
Examine the Oxygen Sensor
- Verify the FiO₂ sensor is connected, powered, and calibrated per manufacturer guidance.
- Look for condensation, debris, or damage on the sensor.
Why: A faulty sensor may give inaccurate readings even if gas delivery is correct.
Run Self-Test / System Check
- Perform the machine’s automated pre-use check.
- Note any warnings or errors related to oxygen supply, low FiO₂, or sensor malfunction.
Why: The Perseus machine’s self-test identifies leaks, sensor errors, or supply issues without disassembly.
Verify Settings
- Confirm FiO₂, tidal volume, and fresh gas flow settings match the intended prescription.
- Ensure no cross-coupled settings or unintended gas blender override.
Why: Operator settings or misconfigurations can mimic equipment malfunction.
If the Problem Persists
Common external causes have been ruled out (hoses, supply, sensor, settings).
The device should be:
- Removed from service
- Labeled Out of Service
- Sent for repair or bench evaluation
Stopping at this point prevents patient risk and avoids unnecessary internal inspection.
Clinical Use Tip
Do not rely on a potentially faulty FiO₂ reading during patient care.
Switch the patient to a verified working anesthesia machine or manual ventilation if FiO₂ mismatch is suspected.
Only troubleshoot when it is safe and the patient is supported on an alternate system.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
“Anesthesia machine FiO₂ shows 40% but set at 60%.”
Cause
What was observed during troubleshooting.
Example:
Observed sensor connected but not calibrated; supply pressures slightly low; hoses intact.
Resolution
What action was taken.
Example:
Verified supply, re-ran self-test, calibrated sensor; FiO₂ matched set value. If unresolved, machine removed from service and sent for repair.
Helpful Details to Include
- Supply pressures for O₂ and air
- Flowmeter settings and readings
- FiO₂ sensor status and last calibration date
- Alarm codes observed
- Vaporizers in use and positions
- Any unusual sounds or leaks
- Final device status after troubleshooting
Final Thought
Logical, stepwise troubleshooting ensures patient safety, prevents unnecessary disassembly, and identifies whether escalation to repair is required. Documenting findings with CCR methodology provides a clear record for future maintenance and regulatory compliance.
That is successful troubleshooting.